Valley-addressable Monolayer Lasing through Berry Phase Photonic Cavities

Spin-valley coupling between circularly polarized light and valley excitons in transition-metal dichalcogenides has offered many opportunities to generate and manipulate spin information by exploiting the valley degree of freedom. Here, we report on the first room-temperature valley-addressable WS₂ monolayer laser, where the spin of lasing is efficiently controlled by the spin of pump in a magnetic-free means. This effect is achieved by integrating a WS₂ monolayer into a Berry phase photonic cavity that supports a pair of orthogonal spin modes with high quality factors. The spin-pumped lasing effectively breaks the population symmetry of valley excitons, resulting in highly coherent emission with valley-switchable radiation modes due to distinct laser thresholds. Our scheme provides a new platform to develop versatile coherent spin light sources at room temperature via actively manipulating spin-valley coupling in light-matter interactions.